As one of methods of integrating a plurality of semiconductor elements, a method of stacking chips is used.
In this method, after separately forming semiconductor elements on semiconductor substrates such as Si substrates, the semiconductor substrates and the semiconductor elements are stacked. Therefore, the semiconductor substrates are necessary for the respective elements. As a result, a reduction in thickness is limited and cost increases. Therefore, as a method of stacking a plurality of semiconductor elements having different functions to form an electric component, a method of, after forming an element on a single semiconductor substrate, continuously forming another element on the semiconductor substrate is proposed (see, for example, Japanese Patent Application Laid-Open No. 2008-140867). Specifically, first, a semiconductor element such as an integrated circuit and a wiring layer are formed. Subsequently, before formation of a functional element such as a MEMS element, a contact hole for electrically connecting the functional element and the wiring layer is formed in an insulating film present between the functional element and the wiring layer. Thereafter, the functional element is formed and a conductive material is filled in the contact hole to electrically connect the functional element and the wiring layer. In this way, an electric component is manufactured.
However, in the electric component in the past, a wiring structure for electrically connecting the semiconductor element such as the integrated circuit and the functional elements is additionally formed in the insulation layer between the semiconductor element and the functional element. Therefore, connection interfaces between the elements increase. As a result, it is likely that wiring structures are not connected on the connection interfaces and reliability of the electric component falls. In the method of manufacturing the electric component in the past, when an interlayer insulating film is formed between elements, formation of a contact hole for connecting the elements, formation of a wiring layer, and the like are generally performed for each interlayer insulating film to be formed. Therefore, the number of steps increases and productivity falls.